Comparison of electric field-dependent property in BaTiO3-based piezoceramics between single and coexisting phases

The evolution of electrical properties with an electric field (E) was compared between single-phase BT ceramic and phase-coexistence BT-based (BTS-0.15BCT) ceramic. The dielectric, ferroelectric, piezoelectric, and strain properties are all found to be electric field-dependent, especially for BTS-0.15BCT ceramic with small domains and easy polarization rotation induced by phase coexistence. High ferroelectric and strain properties are obtained in this ceramic because sufficient domain switching can easily be achieved. The high dielectric constant can be further elevated after poling this ceramic due to the E-induced multiphase transitions. Dynamic piezoelectric measurement reveals that the dynamic piezoelectricity can reach to similar to 740 pC/N, which is much higher than the static value (similar to 620 pC/N) of poled BTS-0.15BCT ceramic. However, the converse piezoelectric coefficient will decrease at high E, because of the quick decrease in dynamic dielectric response caused by clamped polarization at high E. All the results demonstrate that phase-coexistence BT-based ceramic shows electric field-related properties due to the soft structure, whereas it cannot be observed in BT ceramic with stable phase structure and large domains. This work reveals the evolution difference and structure origin of electrical properties in BT-based piezoceramics with different phase structures.